Crossing Lines
by 4waterdragon27
Summary: Life is based on choices. Choices are determined by situations. Tsuna had two possible options in mind to defeat Checker Face; One: the creation of a system to sustain the Trinisette, Two: Fight. Unfortunately, Talbot failed to create the system in time and Tsuna was forced to conquer his despair and battle Checker Face. However, despair led to a new option...And a world of Ninja.


**Crossing Lines**

 **Chapter One**

 _Prologue_

" _Be careful, Tsunayoshi Sawada. Checker Face will try to drag you into the dimension where he actually exists…"_

Even before the horror of the Representative Trials started, Tsuna would admit in that small amount of pride that he carried within himself that he was _strong_. If the situation was any less severe, he would let out an amused laugh. Considering the cowardly person he was before, the confidence he had in himself now showed the amount of progress he made.

And it _wasn't_ confidence based without feats.

 **His** enhanced intuition was capable of dominating the bearer of the Mare Sky Ring, Byakuya, and his ability to see through the timelines.

 **His** strength was _powerful_ enough to escape the attraction of a black hole - a death that even _light_ can't escape - created by his dear friend and leader of the Simon Family, Enma.

 **His** flames were capable of harmonizing with the _Earth Flame_ of his misguided enemy to create the _Oath Flame_ and defeat the overwhelming power of the plotting original wielder of the Mist Ring, Daemon Spade.

And just moments before, Tsuna reached a level that no one could've ever imagined. An eruption of _flames_ surrounded him - all thanks to the _Dying Will Bullet_ that was shot into his forehead by his dear mentor - and sought to overtake him like a wild beast.

It ravaged him, tried to overwhelm him and turn his body to ash. These _flames_ didn't wish to control, they wished to _conquer_ \- both his enemy _and_ himself.

Instead, he _tamed_ them.

Unlike Bermuda who let himself get consumed by the hungry flames, Tsuna took the flames and made himself something more. He gained an understanding of the _Dying Will_ that he was never able to understand before and could see life in a whole different fashion. Tsuna evolved to the point that he was sure that he would be able to activate his _Dying Will Mode_ whenever he wished on command from now on.

Even now he could feel it in the corner of his mind. If he had the energy, he could summon it at any time he wished. It was a comforting feeling, a confidence that he never felt before.

With these flames...He could do _anything._

Even access the other flames with enough practice.

Perhaps, it's because he reached the last stage: _Ultimate Dying Will Mode._ It might've been for that reason that he understood the flames, that he understood the energy within every single human, that he was confident in the fact that he could defeat any opponent before him.

Or perhaps it was the Vongola Intuition.

Regardless of the these thoughts, this power-up made him a being that couldn't be called human.

After all, what human was capable of surpassing the Speed of Light?

All of these facts, all of these powers, they all lead to a single conclusion: he was extremely powerful. It wasn't arrogance. The eyes of everyone surrounding, the nature that _twisted_ at his very presence told him this.

He was _powerful._

So why was he so helpless in this situation?

Tsuna's glowing orange eyes watched, helplessly, as time moved in slow motion. He never believed in the legends that stated Time would slow down and you would have the chance to see your life flash before your eyes until your end.

He never believed it, namely for one reason: if he had time to regret, he had enough time to fight back; however, as he watched his life flicker by, he couldn't find any faults with those legends.

Tsuna could only regret because there was _nothing_ else he could do against his opponent. The potent flames - he wasn't sure if it was a new state or a new flame (like Bermuda) - that surrounded his body during his power-up disappeared, sealed within himself.

Once again, Tsuna could feel the power at the back of his mind. It pleaded, it **begged** , to be released in order to save not just himself, but all of his friends as well.

However, he couldn't.

Exhaustion hungrily ate at his body, trying to rob the last bit of defiance within himself - to defeat the last opponent before him.

He just _couldn't._

He couldn't summon his _Dying Will_ anymore.

He was just so _tired_.

Even now, he could barely find the strength to move his face to take in the forms of his friends. He fought battle after battle, taken on injuries by fighting the Vindice - especially exhausting himself during his fight against Jager - and using all of his strength in the battle against Bermuda _before_ managing to gain more strength.

That is to say: he was fighting on fumes even _when_ he powered up. The fact that he was even able to beat Bermuda spoke of his fortitude, of his will to protect his family.

Tsuna's eyes took in the forms of his friends; they were either watching in despair or unconscious, slowly dying on the ground before him.

Vongola intuition instantly fed him the information of his friends on the battlefield.

Xanxus. Arm sliced off clean seconds into the final fight. Legs? Barely attached to his body - without immediate treatment, Tsuna's intuition told him he'd never walk again. Diagnosis? _Barely Alive._ _Would die without treatment._

Squalo. Taken out seconds within the fight, Jager punched a hole directly through his chest. Through his _heart._ His blood piled onto the ground. He _wasn't_ breathing. _Dead._

Byakuran. Lasted a few minutes into the fight; unfortunately, his beating was continuous. His wings ripped off, seemingly unavoidable even _with_ his abilities to see through parallel worlds. A stab wound on his stomach, blood coloring the ground red. Breathing. Condition: Worsening. Needed immediate treatment.

Dino. A deadly wound running from his shoulder to his hip, barely managed to survive the attack; unfortunately, without any medicine or healing, at the rate he was losing blood at, his death was imminent.

Mukuro. Fought until the end with Hibari and managed to receive the least amount of wounds. Puncture wound on his left rib cage - shallow, not anything too terrible. Unfortunately, received harsher wounds - a deep slash into his shoulder blade. He would survive. However, like the others _needed_ treatment in time.

They could survive with treatment.

Tsuna's intuition told him that would change if Checker Face didn't disappear. His intuition was capable of gathering all the information in this battlefield and also told him that it was _possible_ to save them. Squalo - pronounced dead by his intuition, also told him that he could live if the Mist Arcobaleno did something after the _current_ threat was taken care of.

Unfortunately, even if Viper did whatever he wanted to do, they all needed to still go to the hospital for immediate treatment.

Otherwise, they would die.

His intuition told him all this and _more._

Enma. Diagonal wound. 1.3 feet in length across his back. Unable to move.

Chrome. Stomach cut open. Not too deep, but without care, her death is certain. Too much blood.

Flan. Almost had his spinal cord cut; instead, he received a rather mean wound on his back.

Hibari. A deadly deep wound in his shoulder. Stitches are necessary. Hospitalization to stop the bleeding necessary.

It was of the utmost importance to get them all to the hospital; unfortunately...

He couldn't help them.

How could he help them if he, himself, was helpless.

Tsuna's glared at the hole before him, the tear in the universe that would take him into Checkered Face's Dimension. However, at this point, that tear seemed more and more like a black hole as it dragged him into its dimension.

" _Be careful, Tsunayoshi Sawada. Checker Face will try to drag you into the dimension where he actually exists…"_

Bermuda told him before he could even think about fighting the man. Why didn't he listen? No; the problem wasn't that he didn't listen, the problem was that he was confident he'd be able to defeat the opponent before him.

That he would be strong enough to beat him before he could take him into his dimension.

Tsuna frowned; he never could've imagined that his _Ultimate Dying Will Mode_ would die out so quickly. His eyes flashed through the memories of seconds before…

 **XxCrossing-LinesxX**

" _Do you remember this face?"_

 _It was the jolly, uncaring way he said it. Tsuna frowned; it was as if he found all of their struggles a game, all of the deaths that happened because of_ _ **his**_ _game a_ _ **joke.**_

 _People died today._

 _Because of_ _ **him.**_

 _Tsuna, however, in his Ultimate Dying Will Mode was calm enough to restrain his rage. He couldn't afford to lose control - these flames were overwhelming as they were already._

 _Instead, he confirmed the character in front of him._

" _Kawahira."_

 _Tsuna's response was curt, without the usual respect that accompanied it when addressing someone older than him. However, he couldn't help it. All of the rage, all of his anger - it was all because of this man._

 _Bermuda's hatred._

 _The deaths._

 _The Arcobalenos' deaths._

 _This cycle of killing the previous seven for the new seven - that barbaric practice. Tsuna's intuition told him it was because of the man before him - a theory that was confirmed by his chat with Bermuda._

 _It was all because of him._

 _Tsuna took in all of his words with a seriousness that he never felt before, with a certainty that he would meet his end by his own hand - that is_ _ **if**_ _Checker Face doesn't accept his plan. And even_ _ **that**_ _was half-assed. He asked Talbot to figure out another way; unfortunately, he said it would take a couple days to get it prepared._

 _The change needed to happen today._

" _I can feel how you seethe with anger towards me…" Kawahira placed his mask back on, an infuriating smirk on his face. He shot an amused glance towards Bermuda, "Even though your plan of defeating me…"_

 _Tsuna's intuition prepared him for it even before it struck. The familiar silence before a storm made the rest of the Arcobaleno tense up - recognizing the clear presence of power._

" _Is wrong from the start."_

 _Overwhelming power erupted from Checker Face's body, surrounding his form in Mist Flames - Tsuna made note of that, it would be useful for the battle - and caused his presence to double with every second._

 _Tsuna flared his own flames in response - he was the only one who could possibly handle the monster before him. Their flames battled for supremacy, electricity crackling from the purity of their flames as they met one another. They twirled around one another, attempting to change the other's aura to their own with no success._

 _Tsuna took a deep breath and dug deeper into his Mode and brought out the potency of his flames - the power that surpassed the speed of light._

 _Kawahira met his presence._

 _And surpassed it._

 _Tsuna expected it, was aware it was going to happen in fact - Vongola's intuition came in handy for moments like these - however, Tsuna continued to flare his power into the sky. His orange flames surrounding his body in an aura and shooting into the sky, parting the very clouds above him._

 _His flames were_ _ **their**_ _hope._

 _He couldn't allow it to die out._

 _As long as his friends believed in him, he_ _ **would not falter.**_

 _Checker Face seemed to realize this and simply gave Tsuna a knowing grin. Tsuna realized quickly that he_ _ **hated**_ _that look; the eyes of someone who clearly knows that they're better than you and makes sure to state it._

 _And then suddenly their flames died out._

" _That was about 10x the strength of your flames, Tsuna-kun."_

 _Everyone had their mouths open at the display of power before them and Tsuna growled in annoyance. He knew Checker Face was going to say that in order to make their resistances end._

 _No one could face such overwhelming power._

" _No one besides myself." Tsuna calmly looked at Kawahira, his thoughts continuing, "Only if he doesn't accept my proposal."_

 _However, his proposal was worthless without Talbot._

 _Tsuna listened as Kawahira spoke about the history of the world, how he and Yuni were the last remaining "humans" on Earth._

 _What did that even mean anyhow?_

 _Who exactly were they then? Aliens?_

" _Apparently, when "their" species was alive, our race was alive as well. How can they call themselves the original human race? What would that make up? Perhaps the theory of evolution? We could be those chimps?" Tsuna withheld his laugh, "Which would mean Yuni's ancestor would've produced with a chimp? No I doubt that. Severely. Who are we? Who are our ancestors?"_

 _Unfortunately, Tsuna couldn't focus on those thoughts as Checker Face continued._

" _My species has been living on this planet before your species was even born."_

 _And there goes Tsuna's theories. Perhaps they were actually aliens? How exactly were we born? Maybe we're a crossbreed?_

" _Protecting this miraculous plant, the Earth, was the mission of my people."_

 _Protection? From what? If the Tri-Ni-Set didn't exist wouldn't the earth be destroyed because it's what holding the life force and evolution? Maybe there's more?_

 _What exactly caused Kawahira's species to get wiped out?_

 _Unfortunately, Tsuna couldn't focus on that as Kawahira continued, telling them about the purpose of the Arcobaleno, and how the rings and pacifiers came into creation._

 _He explained the necessity of the Arcobaleno sacrifices._

 _Checker Face said it was in order to protect the Earth._

" _There has to be another way! A way without killing the Arcobaleno and keeping the Trinisette!" Tsuna growled out. Fuck that. He's not letting any of his friends die on his watch! Not while he was still alive!_

" _If there was another way, we'd already be using it - if it was probably anyways. This method is the last one left." Kawahira responded before a smirk made its way on his face, a smirk that told Tsuna everything moved according to his word._

 _It was cocky._

 _Arrogant._

 _Gave off the air of a higher being._

 _And it made Tsuna angry._

" _By the way, Tsunayoshi Sawada-kun, you're worrying about the current Arcobaleno, but you're the first on the list of the new ones…"_

 _Tsuna let out a deep breath, determination pooling in his eyes as he spoke with the greatest conviction, "I'm already prepared."_

 _He took a deep breath, calming his flames and strengthening his intuition to the strongest point. Talbot didn't show up…_

" _However…"_

 _Which means he would fight._

" _That's only_ _ **if**_ _you defeat me!"_

 _Glowing orange eyes opened and his flames flared, erupting in a huge explosion outwards. His energy shot into the sky, blowing back everyone near him - disregarding Checker Face; however, the surprise on his face was more than enough._

 _Before his energy could leave him, Tsuna sucked it all back, covering his body in an orange cloak of flames. It surrounded him like an aura, like the ones that cloaked the DBZ fighters in that anime._

 _Brunette hair danced between two colors, changing from a deep brown to a brilliant yellow as his flames infused themselves into his body._

" _Ho." Kawahira stated, an interested smile on his lips, "There aren't many in this world that are close to coming near my power level. How interesting."_

 _Tsuna squeezed his fist._

" _Unfortunately…"_

 _Tsuna went on his tip toes._

" _If you think you can beat me, you're sorely Mist-"_

 _His words were cut off as Tsuna bursted from his position and smashed his fist into his mouth, hurtling Kawahira backwards at, well,_ _ **extremely**_ _high speeds._

 _Tsuna almost laughed as he looked around before he started to move towards Kawahira once again._

 _Speed didn't quite cut it at this point._

 _Tsuna would've gasped in shock if the situation was any less severe, but he couldn't. He could only glance at his surroundings before continuing to move._

 _But_ _ **damn.**_ _He didn't know_ _ **anyone,**_ _much less himself, could be this fast._

 _Everything was frozen._

 _No one moved._

 _The voices that were shouting out before he moved all but disappeared - they probably didn't even realize he moved. Tsuna was moving at a speed where a second could be an eternity._

 _That's how fast he was moving._

 _In his perspective, everything was frozen._

 _It was like he was in his own little world!_

 _Tsuna didn't even know how his mind was functioning, but it could. Unfortunately, he was pried out of his amazement as Mist exploded over the Kawahira he hit before poofing out of existence - the real Checker Face appearing in front of him._

 _Tsuna's eyes narrowed. "An illusion. A real illusion. Clever. I should've expected that from a Mist User."_

 _However, now that he knew, his intuition could work around it. If Tsuna was in a better state of mind, he'd realize that in this Mode, it shouldn't have happened so quickly. Kawahira's appearance shouldn't have been that fast, his Mist shouldn't have departed so quickly._

 _Kawahira was not capable of moving at his speed._

 _He should've realized that his_ _ **Ultimate Dying Will Mode**_ _was fading away at an extremely fast rate._

 _But he didn't._

 _Not even as Kawahira spoke, an impressed glint in his eyes, "That was...Impressive. Out of everyone who came near my level - out of everyone who was at my level - I've never seen anyone move that fast. If I wasn't an illusion, that would've been annoying to deal with."_

 _Tsuna made note that he said 'annoying' rather than 'hurt'. He would need to be careful._

" _From your battle with Bermuda, I realized that you had the ability to counter people moving at the speed of light; however, I should've realized that when you moved your fist, you moved when Bermuda was right next to you - meaning you punched out at a speed greater than the speed of light." Checker Face gave him an impressed glance, "However, it's not just combat wise. You can actually_ _ **move**_ _at a speed greater than light...Amazing. But I wonder for how long?"_

 _The golden-brunette narrowed his eyes before disappearing in a burst of speed._

 _Tsuna would make sure to hit him this time._

 _Unfortunately…_

" _Your speed is amazing. Godly even...However, your body can't handle it."_

 _It was at that moment Tsuna realized that the flames that covered him in a cloak had disappeared._

 _Completely._

" _It's been displenishing throughout the fight. Perhaps if you weren't fighting on fumes this would've ended differently," Kawahira gave him a sad smile, "It's been fun, Tsunayoshi Sawada-kun. But it's time for the new generation of Arcobaleno to make their appearance…"_

 _Checker Face took his staff and cut through space-time itself. A tear in the universe appeared, right in front of the path that Tsuna was taking towards him. And even if he wasn't, the attracting of the hole was sucking him towards it._

" _The process takes place in here…"_

 _It was over._

 **XxCrossing-LinesxX**

And so here he was - a result of his carelessness, unable to save anyone.

Not even himself.

Tsuna felt his heart clench around him, a void slowly filling his body, consuming the rest of his flames in its emptiness. For the very first time in ages, he felt _alone._

Tsuna didn't even want to imagine the reactions of all of his friends when they realized how _weak_ he was. How incapable he was of protecting the people he loved.

He was useless.

He couldn't do _anything_.

For the first time in a long time, despair overtook him as he looked over the forms of his friends. They were broken, beaten; however, they still held defiance in their eyes. A determination, a loyalty, that Tsuna would defeat the enemy and save them all.

They placed their _hope_ in him.

They _trusted_ him.

They wanted to _help_ him.

This _despair!_ It was crushing, Tsuna couldn't stand this weight. The weight of all his failures, the weight of his incapability to defeat the last enemy and bring them all back to their peaceful lives - however peaceful life in the Mafia would be.

Despair.

 _Despair._

A despair so similar to the one Bermuda felt.

Tsuna gave a dry laugh; he supposed he understood Bermuda even more than he thought he did. He must've felt just as useless when he fought against death, fighting to stay alive to protect his friends or, perhaps, just his own existence.

He felt despair.

Just like Tsuna.

He felt his heartbreak as he watched his guardians try to protect him one last time.

His _guardians_ , his _friends_ ; they all tried to struggle onto their feet in an attempt to help Tsuna. Flames flickered upon their rings, trying to bring upon the will to help their beloved boss.

Their beloved friend.

Even Mukuro, with all of his attempts to capture his body and his claims that he didn't like him, had his red eye alight, eerie purple flames flickering to life. Perhaps it was just his imagination, but they seemed even darker - was he getting sentimental at seeing his friends for the last time?

His eyes caught on Reborn, expecting to see disappointment alight in his eyes for not being able to save him.

For his weakness.

For his worthlessness.

" _I'm sorry...For being the worst student you've ever taught."_

He expected to see all types of negative emotions.

Instead, there was only a single cocked eyebrow.

Tsuna almost laughed; he could already hear his voice in his head, " _Are you serious, Dame-Tsuna? If you die right now, your training will be even more severe."_

Tsuna laughed.

" _I'll tie your arms behind your back and throw you off a mountain and make you climb your way back up."_

He actually laughed.

And a single glint of emotion hid in Reborn's eyes - not disappointment, but _pride._ Pride that Tsuna _would_ defeat Checker Face just like he beat every other opponent before him.

Reborn was absolutely sure he would win.

The void inside of him suddenly filled, brightening with the emotion of hope and determination. The despair that he felt drowned with just a single cocked eyebrow.

How ridiculous! But this was his family.

Tsuna grinned in determination.

The family he would protect!

Tsuna could see Checker Face looking at him with confusion, he could see his friends look up at him like he lost it, and he could _see_ the small smile on Reborn's face.

It was just so silly. He couldn't help but laugh.

Was he really about to give up? The answer was so simple: of course, he could save his friends. There wasn't another option, there was only that one: he would save his friends.

Tsuna's eyes narrowed, " _However…"_

How could he save any one of them if he couldn't even save himself?

He closed his eyes, grasping at the despair that previously enveloped his body. Tsuna understood now, he understood the despair Bermuda felt - the despair of dying, of being useless and unable to accomplish anything, the inability to save the people he loved.

The despair that lead to emptiness.

Tsuna faced it.

He embraced it.

He enveloped it.

He conquered it.

Tsuna's eyes shot open; his eyes glowing a fierce orange as an energy enveloped him, flooding his body with a new found strength.

Tsuna remembered how it felt to be in his _Ultimate Mode_ and while he may not have the stamina to activate it again, his understanding of the _Dying Will_ remained.

The _Flames of the Night_ weren't created by despair. While it may have been the root to the creation of those flames, it wasn't what caused it to ignite. There has always been despair, it's been there from the beginning. These flames were the answer!

Similar to how the _Sky Flame_ was created from mass-violence, it became the answer to war: the flame that fights for peace and understanding, the flame of Harmony...

Tsuna realized this now. Each flame was an answer to one of the questions that pressured humanity since the beginning.

The answer to war? Peace, harmony - the trait of the Sky.

Bermuda found the answer as well! However, he misinterpreted his Flame's answer as the source of its creation. The Flame's source was despair! Bermuda didn't create it _from_ despair! Bermuda created it _because_ of despair.

It was his answer!

It was his decision to fight back!

To rebel against despair!

To **live**!

 _The Flames of the Night..._

Black flames enveloped his hands, trails of a liquid-like shadow moving throughout the air as a dangerous hum resonated throughout the world as if understanding the universe-shaking explosion that was to come.

 _They were created from the rebellion against despair! They were the answer as to how to fight back against it, to defeat the root of despair...They are…_

"BERMUDA!"

Tsuna's glowing orange eyes lit with determination as he made eye contact with him, "The Flames of the Night aren't despair!" Tsuna roared out his conviction, "THE FLAMES OF THE NIGHT ARE HOPE!"

 _Hope for a better future._

 _Hope to survive._

 _The answer that humanity created to despair was_ _ **hope.**_ _Hope that things would get better even if things are looking awful! It's one of humanity's greatest strengths!_

Tsuna didn't look back to make sure he understood it. He didn't look at the shock on the faces of everyone surrounding him as he manifested the shadow-like flames of the Night. The flames that were unique to the Vindice - a flame that made them terrifyingly powerful - was now in the hands of Tsuna.

He didn't look at Hibari's predator-like smirk.

He didn't look at Chrome's awed smile.

Nor at Yamamoto's cheerful grin.

Or at Gokudera's dog-like expression as his Boss evolved once again.

Tsuna didn't look at his exuberant Sun Guardian as he shouted his enthusiasm.

And he didn't look at the proud smile on Reborn's face that was showing for everyone to see.

Tsuna didn't see any of that.

Instead, he made his _Flames_ grow stronger and stronger, willing it to extend along his arm. What he was about to do was _extremely_ risky nor did he know the consequences for what he was about to do.

But he imagined it could be apocalyptic.

He gathered all of the flames into his hand, placed all of his power into creating a single back orb. It was small, the size of an apple; however, he could tell it carried more than enough power to envelop nor just the tear in the universe, but also Checker Face, himself.

Tsuna grinned at Kawahira; he knew he wouldn't be able to escape from his dimensional warp - not with the inexistent amount of control he had over the _Flames of the Night_ ; however, he'd make sure that he wasn't the only one that left this dimension!

And he wasn't talking about heading towards Checker Face's dimension.

Tsuna gripped the orb of darkness in his hand and threw it towards the portal. As he was looking directly at Kawahira, he didn't miss the look of pure horror that crossed his face. As the orb approached the tear, Checker Face tried, and failed, to stop him, "No! You fool! You don't know what could happen if these two attacks meet!"

Tsuna didn't look back at the faces behind him and, as such, missed the glow of Mukuro's red eye as it shifted into the number 7 and locked onto Tsuna's form.

Before the red eye faded away.

He missed all of this.

Checker Face turned red as he screamed in...Anguish?

"YOU'LL SEND US TO A DIFFERENT DIMENSION! WE COULD BE ERASED FROM EXISTENCE! WITHOUT YOU HERE TIME WILL REMAIN FROZEN WITHOUT THE SKY TRINISETTE AT BEST! YOU DON'T KNOW WHAT KIND OF PROBLEMS THIS COULD CREATE!"

Tsuna chuckled as the orb hit the ground.

"You'll destroy this world! We need to create the new generation of Arcobaleno! Don't you understand! The world can't handle it! Not to mention if you disappear the entire world might destabilize!"

Kawahira was gasping at this point, but Tsuna had a serene look on his face.

"As long as I get you away from them, I don't care. Without you here, the Arcobaleno will return to normal." At the look of shock on Checkered Face's face, Tsuna smiled, "Call it intuition."

As the orb expanded and extended towards him, Tsuna's eyes lit up in a warm fashion, looking back at his family.

"Besides, I'll be back. I have a Mafia to lead, after all."

For the first time in his life, Tsuna was able to witness Reborn gaping.

And then there was darkness.

 **XxCrossing-LinesxX**

" _You're reckless."_

 _Tsuna twitched. This wasn't the ideal way to be woken up after the constant struggles he faced. Sure, he wasn't expecting a thank you or a well-done, but he was_ _ **not**_ _expecting to get scolded._

 _Especially by_ _ **him**_ _of all people._

 _Tsuna's response was immediate, "You're...A hypocrite."_

 _The handsome blonde before him with matching orange eyes ignored him and continued with his rant, "You threw the dimensional attack of your Flames of the Night - great job with that by the way." Tsuna rubbed the back of his head bashfully; sure, he was getting scolded, but he was just praised by the man he held on a pedestal. "At a tear in the Universe. Do you know what could've happened?"_

 _Tsuna scratched the back of his head, "Besides saving all of my friends?"_

 _The blonde with the Roman numeral of "I" on his glove groaned, "You could've destroyed the world from the amount of energy meeting or maybe even connected every dimension in existence or even freeze time for eternity!"_

 _Tsuna blinked._

" _Oh."_

 _He really didn't know how to respond to that._

" _Oh is right! That was easily the most simple-minded thing I've ever seen anyone do."_

 _Orange eyes glowed in annoyance as he was scolded by someone he saw as a father-figure, causing him to cross his arms and huff to the sides. Sure he could see how bad it_ _ **could've been**_ _, but it didn't happen. Tsuna bit back, "You would do the exact same thing if you were in my situation!"_

 _Sure Tsuna was being a bit more childish than usual._

 _But this man..._

 _Giotto placed a hand on his head and rubbed his hair affectionately, "That is true." He let out a chuckle, "I guess I should've expected it, we_ _ **are**_ _a lot of like. Nonetheless, I'm proud of you for protecting all of your friends and family. I'm proud of how strong you've become, Tsuna."_

 _Was like the father he never had._

 _Tsuna smiled to the side and mumbled out, "Thanks, Primo."_

 _Was it childish of him to want to say Dad?_

 _They grinned at each other; they really were similar. Hair style, Flames, personalities - they really were like father-and-son._

 _Then Tsuna blinked._

" _Wait what the hell!"_

 _For the first time since awakening, Tsuna realized they were in some golden world filled with clouds and sparkles. They were standing - perhaps floating would be a better word - in a void; there wasn't even a floor! How was he not falling through!_

" _Where are we? This is not normal!"_

 _Giotto ran a hand through his hair before responding, "No. No this is not normal." He let out a sigh, "You've landed us in quite the predicament."_

 _Tsuna raised an eyebrow, "Us?"_

 _Giotto smiled at him before tapping Tsuna's ring, telling him that he was just a projection of his soul from the ring, "Don't tell me you've forgotten. We are all with you in that ring you have there. Honestly, kids these days."_

 _Tsuna scowled, "Shut up! I've had a long day!"_

 _One would say fighting a group of individuals that were hailed as the strongest from generation-to-generation who also happened to possess the ability to warp could be seen as "long". Not to mention his battle against Bermuda where he created a whole new mode - that_ _ **surpassed**_ _the Speed of Light - and proceeded to kick his ass._

 _And then to boot it all off, he faced off against the original "Human" - whom happened to possess 10x the amount of power he had in Ultimate Mode. And then this Mode just had to shut off before the battle even started._

 _So, yes, one could call this a long day._

 _Giotto smiled, "Kidding!" His smile slipped into a thoughtful frown as he brought them back to the previous question, "As to where we are. Well, putting it simply we're on our way to a different world."_

 _Tsuna blinked. Then he gaped like a fish at Giotto, "W-W-What do you mean a different world!"_

 _Surprisingly, Tsuna didn't tremble in fear like usual. His stutter was from the bizarre statement that Primo just muttered._

 _Giotto nodded seriously, "Two dimensional techniques clashing has serious effects. It can destroy worlds, open up portals, create black holes, destroy the concept of time." With everything he listed, Tsuna found himself trembling in fear of what could've happened, "Thankfully, we got a milder consequence and are on our way to a new world."_

 _Tsuna laughed nervously, "Milder…"_

 _Traveling to a different world seems pretty extreme to him; although, he's done it before so it wasn't like it was completely out of the blue._

" _This little golden tunnel is like a road. Once we reach the end we'll enter the new world…" Giotto trailed off as his thoughts branched forward in many different directions._

" _Worlds." Tsuna hummed; that wasn't that bad actually. He already traveled to a different world and, while terrifying, he made it out in one piece. But there was something out of place right now. While he freaked out slightly, Tsuna was extremely calm._

 _It felt almost as if he was already in his Dying Will Mode._

" _You've noticed?"_

 _Tsuna's attention snapped back towards Giotto, "Noticed what?"_

 _Giotto smiled, "You've reached the point where your Hyper Dying Will Mode has started to mix with you. You can freak out, but it's much faster for you to react and calm down. This feeling, this confidence, isn't exactly from your Dying Will - it's from all the experiences you've gained in your Dying Will Mode. It's just being transferred to you. I can tell this from your eyes; they'll remain that fierce orange forever now - just like mine."_

 _Giotto scratched his chin, "To put it into simpler terms: it's like you're always in your Dying Will Mode - not your Hyper Dying Will mind you, but the mode where you always blew off your clothes." Tsuna blanched at those memories, "Of course, now you can control it so there aren't any more of those incidents happening."_

 _Tsuna processed this all, but before he could speak, Giotto continued, "It seems we don't have much time left. So we should cut straight to business: ask the question on your mind."_

 _Tsuna did. He could always talk about his metamorphosis later._

" _This world. Is it another parallel world?"_

 _Giotto shook his head in the negative, "I'm afraid not. Your intuition should feel it too once it's more developed, but the world we're going into is completely different from our own. When your intuition is complete, you can gain knowledge of anything you're heading into."_

 _He'd have to keep that in mind, but for the moment Tsuna was lost. A world completely unlike his own? What would that be like? What is it going to be like?_

 _However, instead of focusing on any of those, only one question remained in his mind._

 _Tsuna frowned, looking up at Giotto, "How am I going to get home?"_

 _If it was a parallel world of his own, it'd be much easier. The dimensional barriers between those would be much easier to cross since he'd just be in a world that_ _ **could've**_ _been. This, however, was a completely different world he was entering, completely unrelated to his own, meaning there was no relationship between the two worlds._

 _Without a proper relationship, it'd be that much harder to get back to his home. That is - if he even could get home._

 _Giotto smiled, "There's only one way: develop the Flames of the Night. Strengthen it to the point where you can create a portal back to this world. That's the only way."_

 _It was a simple solution._

 _However, no one ever said simple was bad. With that single statement, Giotto could see the hope and determination lighting within his eyes like a fire._

 _Tsuna smiled; he could do that. He could train, he's been training all his life after all - forcefully, he might add. A fond glow appeared in his eyes as the image of Reborn flashed through his mind. He supposed it wasn't just Reborn, he started to train by himself in many occasions - to get stronger, to protect his family._

 _He could easily do it again._

 _It was his original plan anyways. The plan on how to defeat Checker Face. Mastering these Night Flames was his first step in getting stronger, in protecting his friends!_

 _And he already had experience with training a Flame already so training the Night should be faster than it was during his training of the Sky! Not to mention, he's seen techniques used with it too!_

 _He almost drooled from all the abilities it offered him._

" _Which brings me to two points. It appears that Checker Face left you a 'gift' before we were transported to a different world as well." Giotto spoke; the way he said gift let Tsuna know that it was anything but it, "Lift up your shirt and look at your stomach."_

 _Tsuna raised an eyebrow, but did it anyways. His mouth opened a bit as he saw the...Tattoo (?) on his stomach._

 _He briefly chuckled at the thought of what his mom would say when she saw this._

 _On his skin, circling his belly button was a black ring. On the black ring was 7 orbs that was placed in a symmetrical fashion while in the center of the ring - where his belly button was - was another black orb, circled by a second smaller ring. On the second ring laid a single orb. The 7 orbs on the first ring connected itself to the second ring through lines, giving it the appearance of some type of wheel._

 _Briefly, he recognized the Kanji on his stomach signifying the various Flames of the Sky and the Single Flame of the Earth._

 _Tsuna whispered, "What is this?"_

 _Giotto replied instantly, "It's apparently a sealing mark."_

 _Tsuna traced the black markings on his belly, finding the Kanji for 'Sky' was in the center of his stomach. His intuition told him the answer, but he asked anyways._

 _Just to make sure if his situation was correct._

" _Sealing Mark? What exactly is it sealing?"_

 _Giotto looked at him grimly, "Your Sky Flames."_

 _Tsuna froze; he knew it, he expected it, but he still couldn't move. The consequences of not being able to use his flames were...Disastrous. Especially considering his current situation. He looked up at Primo in shock, "What? What did you say?"_

 _Giotto responded in the same grim fashion, indicating it wasn't a joke, "He sealed away your Sky Flames, meaning your access to_ _ **Sky Hyper Dying Will Mode**_ _and_ _ **Ultimate Dying Will Mode**_ _is sealed."_

 _Tsuna froze, his mouth widening in shock. His two abilities, the abilities that could save his friends and protect the people he loved, were_ _ **locked**_ _away! He was going into a new world too! How could he protect himself to even get back home in one piece!_

 _He can't protect anyone if he's dead!_

 _Almost as if Giotto read his thoughts, he answered with a playful smile, "However, saying it's a lock means it has a key."_

 _Tsuna looked up at him hopefully, "How?"_

 _Giotto chuckled, "I'm not sure whether Checker Face sealed away your Sky Flames to protect himself from your Ultimate Mode - I don't blame him, that power makes you capable of surpassing the Speed of Light; he's probably afraid that you might reach his level one day with access to that mode - or in order to make sure you die, but either way it helps you."_

 _Tsuna remarked sarcastically, "Glad my death helps me."_

 _But he had to admit that Checker Face_ _ **was**_ _out of his league; perhaps not speed-wise, but his presence was easily 10x stronger than his own. Tsuna managed to send him away for now, but that wouldn't last long. As powerful as he was, Kawahira was probably resourceful enough to find a way back to their world._

 _However, the purpose of sending him away wasn't his plan on defeating him; no, all Tsuna needed was time._

 _Time to prepare._

 _Time to train._

 _Time to get stronger._

 _Time to surpass Kawahira._

 _So what Giotto stated was exactly what he needed._

 _It meant he had to train with his life always on the line - quite motivating if you asked him._

 _Giotto knocked his head softly, telling him to be serious, "Your Ultimate Dying Will Mode is a Trump Card - you probably realized that after only being able to use it for a couple minutes before it died out. It gave you amazing power - making you capable of surpassing the speed of light; however, it exhausts you quickly."_

 _Giotto tapped his ringed seal._

" _This is going to help strengthen the time you remain in that mode. The reason you can't stay in_ _ **Ultimate Sky**_ _for too long is because you dry out your reserves too quickly. This Seal, by making you unable to draw it out, will slowly gather up excess flames and make a pocket where you can drag energy from. This pocket will slowly expand from the excess flames, making it possible for more and more flames to be stored. It pretty much gives you two advantages: one, it will store flames for you to draw on and extend the time you can stay in your_ _ **Ultimate Mode**_ _after you run out of your natural reserves; two: it will slowly expand your natural reserves, making it capable of storing more flames and, as such, stay in your modes for a longer period of time."_

 _Tsuna breathed out in disbelief; those certainly were a lot of advantages. If he could stay in Ultimate Mode for a longer time range, he's be able to protect everyone!_

 _Giotto chuckled, "It's almost like he's trying to help you out."_

 _Tsuna responded as the depressing, realistic portion of his brain took-over, making him speak in a loud, childish manner, "That is if I survive! Sure there are amazing long-term benefits, but how am I supposed to survive the short-term?"_

 _Primo smiled at him as Tsuna freaked out, "You can still go into Hyper Dying Will Mode...Just not with Sky Flames. Just because your Sky Flames are locked, doesn't mean other flames are."_

 _Tsuna eyes narrowed as he quickly put his thoughts together, "The Seal…"_

 _Giotto grinned, "Yup! You probably noticed the eight orbs on the first ring surrounding your sky flames. These are the keys to opening your locks."_

" _You mean…" Tsuna didn't know if he was on the right track, but his intuition was telling him he was correct, "Those keys are Eight Flames,"_

 _Primo nodded, "Correct. Storm, Rain, Lightning, Mist, Cloud, Sun, Night, and Enma's Earth Flame - you can probably access that now because you harmonized with it."_

 _Tsuna looked at him thoughtfully, "So those are the eight keys to open the Seal. What am I supposed to do? Find people with those flames to open them."_

 _Giotto grinned and shook his head, "I swear, it's really like he_ _ **is**_ _trying to make you stronger." Seeing Tsuna's glare at being vague, Primo waved him off and smiled, "The only way for you to unlock your Sky Flames is for you to learn and become proficient with every single one of those flames."_

 _Tsuna blinked._

 _And then he groaned._

" _Why is there never an easy way to do this!" Tsuna cried, banging his head against his palm. "There's always a fucking trial to complete and things to learn."_

 _Giotto laughed softly at his complaints, "Don't worry so much. Use this time to train all you can. The stronger you get, the better you'll be able to protect the people you love."_

 _Tsuna stopped hitting his head and looked into the golden sky above, "I know." The Vongola Decimo let out a breath, "I was just complaining for the last time before I trained my hardest. After I get into that world, I'll train and train until my body breaks. And then I'll return to our world and be with my family again."_

 _Tsuna's eyes lit with determination, "And then I'll defeat Checker Face once and for all."_

 _Primo smiled at the determination in his eyes and rubbed his hair affectionately, "I'm proud of you."_

 _Tsuna smiled at him._

 _Giotto's eyes widened in realization, "Oh yeah! I forgot! Your guardian-"_

 _He was too late to say anymore as the end of the tunnel came towards him._

" _Oh well." Giotto thought, "I can always tell him later if he doesn't realize it himself."_

 _And then they were both drowned by the other side._

 _ **XxCrossing-LinesxX**_

Haku Yuki was not happy.

Despite her best efforts to keep Zabuza from taking on the mission given to them by Gato, he decided to accept regardless of her complaints - not that she would yell at him anyways.

Zabuza Momochi was her master, her most precious person.

Whatever he wished, she would do. Whether it is to kill or sacrifice her own life, she would do it. She'd become a heartless murderer, she'd become an assassin who never fails - if that was what her master wished. Haku was his most useful tool - and she'd do just that: stay useful. Even if it means following Zabuza into a mission that would, doubtlessly, end up badly towards them.

But that was why she was here.

As long as she lived.

As long as she breathed.

She'd make sure that Zabuza would stay alive. So he could make any moronic action he wanted to, she'd always be there to watch his back.

That was her job as his tool.

This was her purpose as indicated by his status of her most precious person.

Nonetheless, this did not excuse that she **did** think that accepting a mission from despicable scum like him was foolish. Creatures like that are more likely to backstab you than hold up their end of the deal.

She withheld a frown; she was a Shinobi.

She could not show any emotion.

But she couldn't stop the sigh from escaping her mouth. They - Zabuza, the Demon Brothers, and herself - had just departed yesterday from Mizu no Kuni to Nami no Kuni in order to take on the job.

As soon as they reached, they were already given a job - a detail that wasn't recorded in the official assignment that was given to them.

The original mission was to assassinate Tazuna, the master bridge builder; however, Gato deemed it fit to change to change the details of the mission. He decided to add on an additional mission by asking them to check out an area that a meteor seemed to have hit; however, it was high up a mountain where none of his men could reach.

And the few men that **did** reach...Disappeared.

Odd, but nothing unusual in their world.

So he wanted the Missing-Nin he hired to do it for them and see if there were any precious materials that were worth bringing back.

Haku allowed a smile to slip upon her face - one would only be able to call it cute as it lit up her face like when light hit snow - as she recalled Zabuza's reaction to the short-haired midget when he told them.

She almost giggled when Zabuza held Gato by the throat as he demanded more work than entailed. This, surprisingly, changed Gato's mind and he immediately doubled the reward if they would do just one tiny favor for him.

Zabuza dropped him after that.

She sighed; sure they were still on the mission, but at least she saw her Master put Gato into his place.

Haku would've killed him if Zabuza didn't move first for showing such disrespect.

So, yes, one would say that Haku was not having a good morning.

Which is what brought her here, blurring up the mountain towards the valley that was hidden at the top. The meteor that hit the mountain was certainly impressive, she could only be thankful that it didn't hit the town below. The loss of life would've been awful…Not that they're doing anything better by serving Gato.

She released a sigh, "Focus on the mission."

Zabuza decided to leave this task for her as he looked for information of the Master Bridge Builder. She was fine with this, Haku wanted to make herself as useful as possible.

As she neared the top, she whistled at the damage the meteor did. It completely destroyed the top of the mountain, giving it a concave appearance rather than its normal tip. Even from here, she could see the massive crater.

It was impressive.

"I wonder if there's a way to call meteors down to earth?" She thought in an amused fashion - probably not, she considered. There's no way for any human to do that.

Haku shook her head as she returned to Gato's words.

"Most of my men couldn't make it up the mountain, the few that did disappeared and never came down. I think there are others trying to harvest the materials on the mountain. I need you guys to get it for me - for double the reward of course."

Haku couldn't sense any chakra so the likelihood of there being other Ninja up there were unlikely. Perhaps, they're suppressing it? She shook her head; the chances of running into a Shinobi who could suppress their chakra from an experienced Sensor was small.

Especially in Nami no Kuni.

It was only when she was nearing the peak that she realized something was wrong. Meteors, while rare, when hitting the ground always destroyed the surrounding area and, if anything survived, there would always be flames.

The scale of damage was certainly fitting of that of a meteor, but the flames weren't red.

They were **black**.

And they didn't move.

They sat perfectly still in the image of a ring, dancing around the circle with black flames in the center. The Flames didn't even act like normal flames; instead of moving and consuming its surroundings, it simply flowed into the air. It looked more inky and shadowy in substance rather than the normal content of flames.

Haku stopped moving and looked warily at the flames.

They **weren't** normal.

She could sense that, but she couldn't **sense** that.

Haku's brow scrunched up cutely; she could see the flames and she could tell they deadly, however, she couldn't sense any chakra in them.

Natural black flames?

Haku frowned; that was the only possible explanation since natural elements don't possess chakra, but she never heard of black flames before.

Her eyes immediately snapped towards the center as the flames within the ring died out, withering away until it became the size of a human body.

And amidst those roaring black flames was a boy. Haku watched, entranced, as those dancing black flames enveloped the sleeping boy, dancing across his body.

"He's not...Burning."

The flames weren't burning him? Did that mean they aren't lethal? If that's the case, why did she feel so anxious about going near those flames?

Then all of those black flames, every single bit, died out all at once, leaving a sleeping boy in the center.

Haku didn't know what to make of the scene before her, but, thankfully, she didn't have to since her body moved on her own as she spotted the injuries on his person.

In a seal-less Shunshin, she appeared before the boy, immediately taking in the extent of his injuries.

"Bruises and fractures. No broken bones."

She, unfortunately, wasn't Medic-Nin nor possessed any of the training; however, she was extremely knowledgeable about the body from her ANBU training and she picked up a few tricks from watching Medics at work.

The way his body fluctuated every other second spoke of injuries that were far worse than he was showing. So either he managed to heal it or it was internal…

Haku Yuki was a ninja of immense talent and potential. Possessing chakra control that was comparable to medics, she was capable of using even the most advanced applications of chakra. She may not have a Sharingan to copy Jutsu, but she could break down a Jutsu from watching enough times and with her medical knowledge...

She raised her hand and channeled her chakra.

Immediately, green flames licked at her left hand as she attempted to get a full diagnosis on him - this time internally as well. While, once again, she was no Medic-Nin and didn't know how to heal the body using chakra, she picked up this handy trick when watching countless times of how patients were healed.

It was simple diagnosis Jutsu, to see what was wrong with the body.

Internally, it read a lot better.

While it showed the same results - bruises and fractures - the immense rate of his heart and blood flow showed that something serious just happened, and he just barely managed to heal himself from it.

But there was something **wrong** with his body.

Something she couldn't quite place.

There was something missing; something **vital.** She rechecked his every organ, but that found that they were all there and working; however, the feeling remained.

There was something missing.

Something impossible.

But **why** couldn't she place it?

His body almost felt **dead?** But his heart was clearly beating. Haku's eyes narrowed, but quickly shrugged it off. First she should help him heal instead of analyzing his body - she could always do that after.

She let out a breath in relief and, for the first time, took the chance to look at the boy before her. He had long spiky brown-golden hair and possessed a peaceful air about him. Wearing rather simple clothes consisting of a black shirt and khaki's, he appeared almost untouched - which was bizarre considering he must've been the meteorite that hit the earth.

There's no other reason why he'd be perfectly in the center of the crater.

She stared at him for a few moments.

He was cute, handsome even.

And then his eyes opened.

Haku let out a gasp as she met his glowing orange eyes - eyes that were completely unnatural. They were bright and gleaming with an untold power. No eye could glow so unnaturally - it wasn't possible.

A Doujutsu perhaps?

His mouth parted slightly as he attempted to speak. She leaned closer, beckoned by his eyes, and barely made out his words.

"...Where am I?"

Before promptly falling back into the embrace of unconsciousness.

"Well…" Haku let out a soft laugh, "Life just got more interesting."

 **XxCrossing-LinesxX**

 **I've always wanted to read a Katekyo Hitman Crossover; however, almost every single one I saw had someone else as a main character. For the Naruto x Katekyo Hitman Reborn crossovers, Naruto was always the main character in the Reborn world.**

 **There's never been a crossover where Tsuna was the main character and in the Naruto-verse. So I decided to make my own where Tsuna already made it to the end of the series (However, he never beat the main villain).**

 **There were only two feasible ways of Tsuna getting into the Naruto-verse. One is the cliche of the Ten-Year Bazooka which could have a malfunction or be tweaked a bit. The other was the moment when Bermuda said Kawahira would drag him into his dimension.**

 **The unpredictability of two dimensional attacks has unknown consequences so Tsuna's transfer from his world to the Naruto-verse was one of the infinite amount of possibilities. Unfortunately, I had to make Kawahira and Tsuna clash instead of coming to an agreement to make this happen.**

 **Which was seen when Talbot didn't arrive and the urgency of the new Arcobaleno. Without Talbot, Tsuna had no choice but to fight.**

 **Anyways that's how I came up with the idea. Tsuna's position in this story is going to be enjoyable to write. Hope you guys enjoyed!**

 **As you can tell from Haku's point of view, you know where we are in the timeline of the Naruto-verse. Let's see if Tsuna can make any differences! See you next time!**

 **Make sure to provide me some reviews, favorites, and follows if you enjoyed!**


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